1. Field of the Invention
The present invention relates to an apparatus for measuring the seat weight including the weight of a passenger seated on the car seat and, more specifically, to a seat weight measuring apparatus having advantages including that the production cost and the assembling cost of such apparatuses may be reduced.
2. Description of the Related Art
Automotive vehicles are equipped with seat belts and air bags as equipment for ensuring the safety of the passenger. In recent years, an effort has been underway to enhance the performance of the seat belt and/or the air bag by controlling these devices in accordance with the weight or the posture of the passenger. For example, the quantity of gas used to deploy the air bag or the speed of deployment could be controlled. Further, the amount of pretension of the seat belt could be adjusted in accordance with the weight and posture of the passenger. To this end, it is necessary to know the weight of the passenger sitting on the seat by some technique. The position of the center of gravity of the passenger sitting on the seat could also be referenced in order to estimate the posture of the passenger.
As an example of a technique to determine the weight or the center of gravity of the passenger of this type, a method of measuring the seat weight including the passenger's weight by disposing the load sensors (load cells) at the front, rear, left and right corners under the seat and summing vertical loads applied to the load cells has been proposed in Japanese Unexamined Patent Application Publication No. H11-304579, the disclosure of which is hereby incorporated by reference. Through this proposed method, the position of the center of gravity of the passenger sitting on the seat can be known.
Since a seat weight measuring apparatus of this type is intended for use in general automotive vehicles, the cost of the apparatus must be as low as possible. In addition, the wiring and assembly also must be easy. Keeping such subjects in mind, the object of the present invention is to provide a seat weight measuring apparatus having such advantages that the production cost and the assembling cost may be reduced.